Fast optimization of survivable WDM mesh networks based on multiple self-healing rings

This paper presents a fast approach to interactively designing optimal resilient WDM mesh networks based on an optimization engine that, given the network layout, the light path demands and the cost function, sub-optimally selects a ring cover and, for each lightpath demand, the route and the protecting rings. The three selections are made jointly as it has been demonstrated that a 15% cost reduction can be achieved in this way when compared to a sequential selection. The optimization engine, based on Simulated Annealing, yields satisfactory solutions with CPU times ranging from seconds to few minutes, thus allowing user interactive design of the system. In addition, the inherent flexibility of SA allows us to minimize the system cost under various Multi-WSHR protection schemes, including Dedicated-Path-switched WSHR and Shared-Line-switched WSHR. A last feature of the proposed approach is the capability to handle network designs in which, due to particular network layout and/or technology constraints, not all the lines of the mesh can be protected. Under these circumstances, the lightpath demands routed on the unprotected lines are minimized.